Abstract: Objective：To analyze the correlation between the clinical indications of prenatal diagnosis and the chromosomal abnormalities of fetal cord blood in the second and third trimester, so as to evaluate the application of cordocentesis in the prenatal diagnosis. Methods：Cordocentesis were performed in 175 pregnant women with the indications of prenatal diagnosis. Fetal chromosomal karyotypes were examined. The constituent ratio of clinical indications and the detection rate of chromosomal abnormalities were assessed. Results：17（9.71%） chromosomal aberrations were detected in fetal cord blood of 175 cases. Trisomy consisted of 76.47% (13/17) of all abnormalities, including 8 cases with trisomy 21 and 5 cases with trisomy 18. Two fetuses were diagnosed with sex chromosomal abnormalities, one fetus with chromosomal translocation, and one fetus with chromosomal inversion. The indications of cordocentesis were consisted of the soft marker abnormalities in fetal ultrasonic, the high-risk in serum screening, abnormal reproductive history, advance maternal age, fetal sonographic structural anomalies, and the high-risk in NIPT. The detection rate for above indications were 6.12% (3/49), 9.38% (3/32), 0 (0/29), 5.00% (1/20), 33.33% (5/15) and 80.00% (4/5), respectively. Conclusions：The detection rate of chromosomal aberration in pregnant women with fetal sonographic structural anomalies and high-risk NIPT is relatively high, and trisomy 21 and trisomy 18 are the leading fetal chromosomal abnormalities in the second and third trimester.

Key words: Prenatal diagnosis, Ultrasonography, prenatal, Chromosome disorders, Karyotyping, Cordocentesis